a. Field of the Invention
The invention generally relates to fluent material handling apparatus and more particularly to a sample container washing and draining apparatus for a sampler having successive sample containers.
b. Prior Art
In a prior application, now U.S. Pat. No. 4,098,305 entitled Continuous Liquid Sampling Apparatus and Method, assigned to the assignee of the present invention, a continuous sampler is disclosed in which sample containers arranged in a queue are each successively moved to a position where a sample hose or probe is inserted into the sample container to remove fluid sample material by suction. After sample removal, another hose or probe directs a wash solution into the sample container which is removed after washing through the same or another hose or probe. The sample container is tilted approximately thirty degrees during these operations but fluids still enter and leave the sample container while it is generally in an upright position.
While this type of fluent handling is useful in sampler applications where low amounts of sample cross-contamination are tolerable, it is not useful where such low amounts of sample cross-contamination are intolerable. In continuous samplers of the type described in said prior application, and similar devices which inject and withdraw samples through the top of the sample containers, about one to two per cent of the sample and washing solution remains after sample removal and washing are completed. When using samplers to detect low concentrations of materials which may affect public health, such cross-contamination taints sample measurements. Continuous samplers are useful in remote sampling of rivers, sewers and the like where unattended, continuous sampling, such as one-an-hour, around-the-clock, is necessary. Increasing concern for measurement accuracy in certain applications, such as public health, requires substantial reductions in sample cross-contamination.